The origin of groundwater salinity in the Matanza-Riachuelo aquifer system, Argentina
Groundwater salinization is a severe worldwide issue affecting many coastal aquifers by threatening their freshwater resources (Werner et al., 2013; Michael et al., 2017). The Matanza-Riachuelo River Basin (MRRB) is a coastal-continental basin that supplies fresh water to the Greater Buenos Aires co...
| Autores: | , , , |
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| Tipo de documento: | artigo |
| Estado: | Versión aceptada para publicación |
| Data de publicação: | 2022 |
| País: | España |
| Recursos: | Consejo Superior de Investigaciones Científicas (CSIC) |
| Repositório: | DIGITAL.CSIC. Repositorio Institucional del CSIC |
| OAI Identifier: | oai:digital.csic.es:10261/285232 |
| Acesso em linha: | http://hdl.handle.net/10261/285232 https://api.elsevier.com/content/abstract/scopus_id/85143735429 |
| Access Level: | Acceso aberto |
| Palavra-chave: | Old saline sources Groundwater salinity Matanza-Riachuelo aquifer system Modeling mixing |
| Resumo: | Groundwater salinization is a severe worldwide issue affecting many coastal aquifers by threatening their freshwater resources (Werner et al., 2013; Michael et al., 2017). The Matanza-Riachuelo River Basin (MRRB) is a coastal-continental basin that supplies fresh water to the Greater Buenos Aires conurbation, encompassing approximately 10% of Argentina's population. Among other environmental degradation issues, salinization is one of the most important processes affecting the MRRB. In this study, salinization across the MRRB was unraveled using major (Cl, HCO3, SO4, Na, Ca, Mg) and tracer (Br) solutes, together with stable (18O, 2H, 13C) and radioactive isotopes (3H, 14C). Three different saline end-members were identified: Upper Basin Slightly Saline (UBSS), Lower Basin Highly Saline (LBHS), and Lower Basin Hyper Saline (LBHPS). The salinity of the UBSS and the LBHPS end-members was associated with the Miocene Paraná Formation connate marine water, while the salinity of the LBHS end-member were associated with the Pleistocene to Holocene Postpampeano Sediments connate seawater. The estimated 14C values were related to travel time differences in the flow paths delivering water to different zones of the Puelche Aquifer. Groundwater in the upper basin sector of the Puelche Aquifer was likely to belong to long, regional groundwater flow recharged outside the MRRB boundary. Groundwater in the top of the Puelche Aquifer at the lower basin comes from the Upper Aquifer through vertical transfer. This study contributes to a better understanding of (1) salinization processes linked to connate marine water of different ages in the Matanza-Riachuelo Aquifer System and (2) different sources of flow paths delivering groundwater to the upper and lower sectors of the confined Puelche Aquifer. The knowledge generated from this study can help to understand groundwater salinization processes in other aquifer systems around the world and support groundwater management plans across the MRRB. |
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